Influence of glycemic control on viscosity and density of plasma and whole blood in Type-1 diabetic patients

The hemorheological properties of blood play an important role in determining blood flow. Blood inertia, as characterized by blood density, controls blood flow in the large arteries, whereas blood viscosity becomes increasingly important with decreasing vessel diameter. In order to evaluate the impact of glycemic control on the rheological properties of blood, we examined viscosity (shear range: 600-0.2 s(-1)) and density of plasma and whole blood in 26 Type-1 diabetic patients and in 24 healthy controls, matched for age and sex. The diabetic subjects were subdivided into two groups according to their degree of glycemic control: 14 patients with good (HbA(1c) = 7.1 +/- 0.6%), and 12 patients with poor control (HbA(1c) = 8.7 +/- 0.7%). Diabetic patients as a whole did not differ from healthy controls in any of the rheological parameters. subdivision of the patients due to their degree of glycemic control led to a marked rheological separation of Type-1 diabetic subjects with significantly lower plasma (P < 0.008) and whole blood viscosity (P < 0.03 at 10 and 25 s(-1)), and plasma density (P < 0.05) in well controlled patients. Compared with healthy controls, well controlled diabetic patients had significantly lower values of viscosity (P < 0.005) and density (P < 0.05) of plasma. Poorly controlled patients, on the other hand, did not differ from healthy controls in the examined rheological parameters. There seems to be a positive influence of good glycemic control on hemorheology in Type-1 diabetic patients.